Based on the basic principle of the stimulated polariton scattering process, the operation characteristics of terahertz-wave parametric oscillators （TPOs） using the LiTaO3 （LT） crystal, including the ability of frequency-tuning, THz gain and absorption coefficient and the output directivity of THz wave through the arrayed Si-prism coupler, is theoretically discussed in detail. It is found that the excellent performance of LT-TPO can be achieved through the employment of the short-wavelength pump, the high pump energy and short cavity for TPO, based on the characteristics of the A1-symmetry polariton mode and the outstanding nonlinear optical properties of LiTaO3, which is then proved to be a promising candidate material for TPO. The research results provide a useful guide for the future practical operation of LT-TPO.